1. Field
This invention is in the field of toy vehicles, and particularly relates to self-powered miniature toy vehicles capable of negotiating steep and irregular surfaces.
2. Prior Art
Previous toys of the type described above, whether powered by wind-up springs, electric motors or otherwise, have been relatively large--to accommodate conventional gear trains, as well as power sources and electrical or spring motors.
Some four-wheel-drive toy vehicles have made use of chain or belt drive to convey power between the axles; such drive tended to impede "ground" clearance between the axles as well as detracting from ruggedness and reliability of the toy. In addition, miniaturization of prior four-wheel-drive toy vehicles has been hindered by the space required for multistage gear trains preceding the belt or chain drive.
To overcome inadequate traction, many prior climbing toys have had cogged wheels--i.e., have used gears for wheels--and have been adapted primarily for climbing cogged tracks.
An object of our present invention is to provide an unusually small four-wheel-drive toy vehicle able to climb extremely steep and irregular surfaces without belt or chain drive or cogged track.